Various electrical appliances for home or light industrial use, such as the orbital waxer/polisher shown in U.S. Pat. No. 4,791,694, the teachings of which are hereby incorporated by reference, incorporate dc motors. Such motors are relatively light and inexpensive to manufacture. However, the use of a dc motor requires the presence of a rectifier assembly for converting single phase ac to dc for application to the armature windings of the motor.
Heretofore, such rectifier assemblies were typically positioned either remote from the motor housing, or were supported by the outside of the housing. Such positioning of the rectifier assembly requires extensive wiring and discrete conductors passing through the motor housing. While such rectifier assembly location operated satisfactorily, it is always desirable to reduce the number of components and promote ease of manufacture of such dc motor assemblies.
U.S. Pat. No. 3,078,409 to Bertsche, Jr., et al., discloses an electrical power converter including an end frame formed of metal. The end frame is provided with threaded bores which receive rectifier plugs . The converter also includes a subframe which is electrically isolated from the end frame. As shown in the electrical schematic of FIG. 5, the end plate serves as the ground. A terminal bolt, extending through the end plate and insulated therefrom by a sleeve, is connected to the subframe and serves as the positive terminal of the bridge rectifier.
U.S. Pat. No. 3,527,971 to Means illustrates a dynamoelectric machine having a pair of metal mounting plates disposed inside of the motor housing and into which diodes are embedded.
U.S. Pat. No. 4,769,572 to Voigt discloses diodes forming a bridge rectifier mounted on the inside surface of the end shield of the motor. Similarly, U.S. Pat. No. 3,924,147 to Tarnow et al. teaches an insulating plate positioned inside of the motor housing and which supports diode rectifiers.